Informal Business Letter
Writing an informal business letter is a misleading task. When the writer thinks informal, they believe they can write the letter in a tone they would use at home during the weekend with friends. This is far from the case in professional environments. Rather than being completely formal in all of your business letters, you can lighten the tone up somewhat when informal letter communication is used on internal documents that are only between two people that communicate frequently in this manner. Close business associates, business friends, causal individuals, and anyone you are generally comfortable with, would qualify for the informal business letter style, so long as the business letter will not be read by an outside audience.
You can appropriately use an informal business letter when writing business emails, on hand-written notes, short memorandums, types notes, and other similar documents that will only be used internally to the above listed individual types. Always remember that anyone at any time can become offended if you are too informal in your business letters. As a business owner, this shows a complete lack of professionalism. As an employee, offending another employee for being too informal or comfortable can result in termination. Remember that you are working and professionalism should be maintained during business hours. Informal business letters can show your personality, but always proof read and put yourself in the mindset of the recipient to avoid potential problems.